Multiply or Divide?
Concept
The Big Idea
Going to a smaller unit means you need more of them, so multiply. Going to a bigger unit means fewer, so divide.
Example
Metres to centimetres
One metre is centimetres, so metres is centimetres — more of a smaller unit.
In Plain Terms & More Examples
Concept
In plain terms
Changing to a smaller unit needs more of them, so multiply; changing to a bigger unit needs fewer, so divide.
Example
Kilometres to metres
One kilometre is metres, so km m.
Example
Minutes to hours
One hour is minutes, so min hours.